Assembly lang ics 233 dr a r naseer 19 processor

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& Assembly Lang ICS 233 @ Dr A R Naseer 19 Processor – Datapath – Control Memory & Storage Main Memory Disk Storage Input devices Output devices Bus: Interconnects processor to memory and I/O Network: newly added component for communication Components of a Computer System Computer Memory I/O Devices Input Output B U S Control Datapath Processor Disk Network Lecture Slides on Computer Arch & Assembly Lang ICS 233 @ Dr A R Naseer 20 Input Devices Logical arrangement of keys 0 1 2 3 c d e f 8 9 a b 4 5 6 7 Mechanical switch Spring Key Cap Contacts Membrane switch Conductor-coated membrane
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11 Lecture Slides on Computer Arch & Assembly Lang ICS 233 @ Dr A R Naseer 21 Output Devices Laser printing Rollers Sheet of paper Light from optical system Toner Rotating drum Cleaning of excess toner Charging Heater Fusing of toner Lecture Slides on Computer Arch & Assembly Lang ICS 233 @ Dr A R Naseer 22 Output Devices Laser printing Rollers Sheet of paper Light from optical system Toner Rotating drum Cleaning of excess toner Charging Heater Fusing of toner Charging a photoconductive selenium (or other) coated drum. Discharging the drum with the laser steering engine in accordance with the input image rasterized pattern. (the laser is modulated to generate a predefined pixel pattern on the face of the drum - the focal plane). The rotating drum attracts toner to the charged pattern (latent image) generated by the laser. The toner is transferred from the drum to the moving paper to generate a full image. The paper carrying the toner moves through the heater to fuse the toner to a fine non-erasable image. In general the principle of electrostatic laser printing is as follows:
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12 Lecture Slides on Computer Arch & Assembly Lang ICS 233 @ Dr A R Naseer 23 Memory Devices Volatile Memory Devices – RAM = Random Access Memory – DRAM = Dynamic RAM 1-Transistor cell + trench capacitor Dense but slow, must be refreshed Typical choice for main memory – SRAM : Static RAM 6-Transistor cell, faster but less dense than DRAM Typical choice for cache memory Non-Volatile Memory Devices – ROM = Read Only Memory – Flash Memory Lecture Slides on Computer Arch & Assembly Lang ICS 233 @ Dr A R Naseer 24 Arm provides read/write heads for all surfaces The disk heads are connected together and move in conjunction Track 0 Track 1 Recording area Spindle Direction of rotation Platter Read/write head Actuator Arm Track 2 A Magnetic disk consists of a collection of platters Provides a number of recording surfaces Magnetic Disk Storage
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